Sources of Conductivity and Doping Limits in CdO from Hybrid Density Functional Theory
Sources of Conductivity and Doping Limits in CdO from Hybrid Density Functional Theory
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DOI：
10.1021/ja204639y
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发表时间：
2011-09-28
影响因子：
15
通讯作者：
Watson, Graeme W.
中科院分区：
文献类型：
--
作者：
Burbano, Mario;Scanlon, David O.;Watson, Graeme W.
CDO作为一种典型的宽禁带透明导电氧化物，具有优异的n型性能，几十年来一直被人们研究。尽管如此，CDO的导电性来源和p型CDO的缺乏仍然存在不确定性，尽管相对于其他宽禁带氧化物，它的价带最大值(VBM)很高。在本文中，我们利用屏蔽混合密度泛函理论研究了CDO中的本征缺陷和氢杂质，并首次确定了该体系中载流子的来源。我们解释了为什么CDO中的氧空位起到浅施主的作用，而不是表现出与所有其他宽禁带n型氧化物类似的负U行为。我们还证明了p型CDO是不可能实现的，因为n型缺陷在所有的生长条件下都占主导地位。最后，我们估算了理论掺杂极限，并解释了为什么合适的n型掺杂会引起较大的Moss-Burstein位移，从而使CDO透明。
CdO has been studied for decades as a prototypical wide band gap transparent conducting oxide with excellent n-type ability. Despite this, uncertainty remains over the source of conductivity in CdO and over the lack of p-type CdO, despite its valence band maximum (VBM) being high with respect to other wide band gap oxides. In this article, we use screened hybrid DFT to study intrinsic defects and hydrogen impurities in CdO and identify for the first time the source of charge carriers in this system. We explain why the oxygen vacancy in CdO acts as a shallow donor and does not display negative-U behavior similar to all other wide band gap n-type oxides. We also demonstrate that p-type CdO is not achievable, as n-type defects dominate under all growth conditions. Lastly, we estimate theoretical doping limits and explain why CdO can be made transparent by a large Moss-Burstein shift caused by suitable n-type doping.